Catalogue transmissions are listed in very many versions or variants (types of fastening, ratios, constructions sizes, shaft arrangements, etc.) in usually comprehensive catalogues of the manufacturers. Most tasks can be performed with catalogue transmissions of this type. Moreover, in contrast to special transmissions, they can be delivered quickly and also cost-effectively in small quantities.
So that this large number of versions or variants can be delivered quickly and cost-effectively, modular transmission systems are used nowadays, which manage with a small number of parts manufactured and intermediately stored in relatively large batches, to produce a large number of versions or variants of modular transmissions.
Thus, German Published Patent Application No. DE 199 17 145 A1 discloses a modular transmission system which uses spur gears and flat gears.
German Patent No. DE 197 33 546 C describes a modular transmission consisting of two or more transmission modules of identical or different type of construction, which in each case comprise one or more transmission sizes and, within a size, one or more ratios and of which at least one transmission module is an angular gear in the form of a crown gear, whilst a spur toothing of the electric motor can also engage into a crown wheel.